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From: Martin Sperl <kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
To: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
Cc: "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"linux-rpi-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org"
	<linux-rpi-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>,
	"linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Lee Jones <lee-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Subject: Re: [PATCH 1/2] spi: bcm2835: add spi-bcm2835aux driver for the auxiliar spi1 and spi2
Date: Tue, 28 Jul 2015 08:18:25 +0200	[thread overview]
Message-ID: <836DA157-3072-441A-A160-E1FDBB119E88@martin.sperl.org> (raw)
In-Reply-To: <55B6EE1A.2070605-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>

Hi Stephen!

> On 28.07.2015, at 04:51, Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> wrote:
> 
> 
>> If this is not acceptable, then where should such a driver go in the
>> kernel tree?
>> 
>> It would essentially implement the following:
>> bcm2835aux_enable(dev, device-id);
>> bcm2835aux_disable(dev, device-id);
>> 
>> Which would just set/clean the bits in the register while holding a lock.
> 
> That sounds reasonable. I'd also expect a function that the client
> drivers could call during probe() to look up the device (and implement
> deferred probe) and another to release the reference during the client's
> remove().
But the bigger question you have not answered is: “where should such an
auxiliar driver go in the kernel tree?” i.e. which directory?

I really do not want to implement it and then get told: “that should not
go here” - been thru too many iterations already…

Also I am not sure I understood the “defer” thingy.
I thought of actually implementing only 2 functions to use during probe
and removal:
* bcm2835aux_enable(dev)
* bcm2835aux_disable(dev)

Both would pick up the “bcrm,aux” property from the device tree (as per 
“bcrm,aux = <&bcm2835aux 4>”) and set the enable register accordingly
holding a lock.

I still could leave those 2 functions in the spi driver for now and
when someone wants to implement the uart1, then they would need to pull
that out into a separate driver.

As for interrupt-handler: it was a simple idea that would work fine for
the bcm2835aux case to avoid configuring things for the uart, but then
you do not want the uart1 to get configured as 'compatible=“ns16650”;’
inside the device-tree, so this is not acceptable anyway (unless there
were some way to define “additional” compatibility for a driver without
modifying the driver itself).
This means we will need to implement a minimal driver for uart1 that
wraps ns16650.

But as all the drivers (spi-bcm2835aux as well as ns16650) can use
FIRQ_SHARED (and do not need to read/write the shared aux_irg registers)
the need for a interrupt controller is not there.



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  parent reply	other threads:[~2015-07-28  6:18 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-22 13:40 [PATCH 1/2] spi: bcm2835: add spi-bcm2835aux driver for the auxiliar spi1 and spi2 kernel-TqfNSX0MhmxHKSADF0wUEw
     [not found] ` <1434980408-4086-1-git-send-email-kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2015-06-22 13:40   ` [PATCH 2/2] dt: brcm,bcm2835-aux-spi: add binding documentation for new spi-bcm2835aux kernel-TqfNSX0MhmxHKSADF0wUEw
     [not found]     ` <1434980408-4086-2-git-send-email-kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2015-06-22 17:55       ` [PATCH 2/2] dt: brcm, bcm2835-aux-spi: " Stefan Wahren
     [not found]         ` <55884C2B.8040601-saaNCTdWVBT7BZbvpMY5sg@public.gmane.org>
2015-06-22 19:19           ` Martin Sperl
2015-06-22 14:08   ` [PATCH 1/2] spi: bcm2835: add spi-bcm2835aux driver for the auxiliar spi1 and spi2 Noralf Trønnes
2015-06-22 14:55   ` Jakub Kiciński
2015-06-22 15:26     ` Martin Sperl
     [not found]       ` <E72B3D8C-EA1B-4B4C-8EAF-C14A5631882E-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2015-06-25 14:19         ` Martin Sperl
     [not found]           ` <97C7561C-6D67-4F51-94BB-3B8D401D77A0-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2015-06-30  9:42             ` Mark Brown
     [not found]               ` <20150630094232.GM11162-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
2015-07-01 19:39                 ` Martin Sperl
     [not found]                   ` <6A2CCE70-5DAF-4E86-A0A4-F5E93FD1B540-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2015-07-01 20:57                     ` Noralf Trønnes
     [not found]                       ` <55945448.7010502-L59+Z2yzLopAfugRpC6u6w@public.gmane.org>
2015-07-05  1:14                         ` Martin Sperl
     [not found]                           ` <1400E1A3-43E1-4D0E-A54D-E5D668A4C516-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2015-07-05 10:37                             ` Noralf Trønnes
     [not found]                               ` <55990904.9040002-L59+Z2yzLopAfugRpC6u6w@public.gmane.org>
2015-07-05 13:11                                 ` Martin Sperl
2015-07-11  4:41                             ` Stephen Warren
2015-07-11  4:37         ` Stephen Warren
2015-07-11  4:53   ` Stephen Warren
     [not found]     ` <55A0A150.3060809-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
2015-07-12  2:10       ` Martin Sperl
     [not found]         ` <ECFBB7BF-1316-4565-B1F2-FB2651131882-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2015-07-14  4:56           ` Stephen Warren
     [not found]             ` <55A49662.3000706-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
2015-07-14 12:39               ` Martin Sperl
     [not found]                 ` <2768BFA9-7FE9-4EDC-8692-AC3F070BD874-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2015-07-22  1:55                   ` Stephen Warren
     [not found]                     ` <55AEF828.20908-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
2015-07-22 16:28                       ` Martin Sperl
     [not found]                         ` <0125992E-40F4-4702-8404-2943FF9A8788-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2015-07-24  4:09                           ` Stephen Warren
     [not found]                             ` <55B1BA7A.1090104-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
2015-07-24  6:47                               ` Martin Sperl
     [not found]                                 ` <9005ABEC-C60A-4814-AD60-AD5BB09808F2-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2015-07-28  2:51                                   ` Stephen Warren
     [not found]                                     ` <55B6EE1A.2070605-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
2015-07-28  6:18                                       ` Martin Sperl [this message]
     [not found]                                         ` <836DA157-3072-441A-A160-E1FDBB119E88-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2015-07-28 10:48                                           ` Martin Sperl
     [not found]                                             ` <55B75E07.1080104-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2015-07-29 16:37                                               ` Stefan Wahren
     [not found]                                                 ` <55B9014C.7020105-saaNCTdWVBT7BZbvpMY5sg@public.gmane.org>
2015-07-29 17:25                                                   ` Noralf Trønnes
2015-07-29 21:16                                                   ` Martin Sperl
     [not found]                                                     ` <C767C9AD-A9B5-428F-A207-D67269B380C6-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2015-07-30  5:36                                                       ` Stefan Wahren
     [not found]                                                         ` <55B9B7EF.2070108-saaNCTdWVBT7BZbvpMY5sg@public.gmane.org>
2015-07-30  6:45                                                           ` Martin Sperl
     [not found]                                                             ` <C2C16277-C6C1-4F86-BB88-580CF667EF24-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2015-07-30  7:10                                                               ` Martin Sperl
     [not found]                                                                 ` <97861F80-CF83-4FF2-B96E-CDFB1A8F4921-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2015-07-30 15:27                                                                   ` Martin Sperl
     [not found]                                                                     ` <E9EEB426-95DE-4785-949C-6A402A25E115-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2015-07-31 18:42                                                                       ` Stefan Wahren
2015-08-01  2:55                                               ` Stephen Warren
2015-08-01  2:51                                           ` Stephen Warren

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